Stabilizing excipients for therapeutic protein formulations

ABSTRACT

The invention encompasses therapeutic formulations comprising a protein active ingredient and a stabilizing excipient, methods of improving stability in a therapeutic formulation comprising a protein active ingredient by adding a stability-improving amount of a stabilizing excipient to the therapeutic formulation, and methods of reducing adverse infusion-related effects in a patient, comprising administering to a patient in need thereof a therapeutic formulation comprising a protein active ingredient and a stabilizing excipient.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/647,669, filed on Jul. 12, 2017, claims the benefit of U.S.Provisional Application Ser. No. 62/361,793, filed Jul. 13, 2016. Theentire contents of the above applications are incorporated by referenceherein.

FIELD OF THE APPLICATION

This application relates to formulations for stabilizing therapeuticproteins.

BACKGROUND

Aqueous formulations of therapeutic proteins (e.g., antibodies) aresusceptible to degradation through a number of different mechanisms andas a result of several types of stress conditions. In general,degradation of a therapeutic protein formulation occurs when the proteinstructure is altered slightly from its fully folded conformation(partial unfolding) exposing hydrophobic residues that interact with anadjacent protein molecule in solution forming an irreversibleassociation. Certain stress conditions such as agitation, freeze/thawand increased temperature can induce greater protein unfolding leadingto accelerated aggregation of the protein and degradation of the proteinformulation. Degradation of the protein formulation can be manifested byprotein denaturation, the formation of visible particles, the formationof aggregates, the formation of subvisible particles, opalescence of theformulation, loss of biological activity, loss of percent monomer, lossof yield during production and purification, and the like. Exposure ofthe protein formulation to a liquid/air or liquid/solid interface, suchas in agitation or freeze/thaw conditions, allows for a portion of theprotein to unfold because of the lack of water at the interface tostabilize the folded structure through hydrogen bonding and hydrophobiceffects. Other mechanisms leading to protein degradation includeoxidation, hydrolysis, proteolysis, photodegradation, and microbialdegradation. It would be desirable to provide a therapeutic proteinformulation with improved stability to make the therapeutic proteinsmore resistant to the stress conditions encountered during theirdistribution and storage. For example, formulations of therapeuticproteins can encounter stress conditions like freeze/thaw cycles,agitation, long term storage, pumping, filtration, or unrefrigeratedstorage, where improvements to stability would be advantageous.

In conventional protein formulations, a small amount of a nonionicsurfactant, typically Polysorbate 80 or Polysorbate 20, is added tocompete with the protein for interfacial surfaces to reduce proteindegradation that occurs with its exposure to such surfaces. However,polysorbates themselves can degrade, either through hydrolysis oroxidation, and the resulting degradation products promote aggregationand/or reduce solubility of the protein and destabilize proteinformulations. Polysorbates also pose a problem during the manufacturingprocess of protein therapeutics because of their tendency to formmicelles. The formation of micelles can prevent some of the polysorbatefrom passing through filters such as during anultrafiltration/diafiltration unit operation, causing a significantlylarger polysorbate concentration in the drug substance than intended.For these reasons it is desirable to have a protein formulation thatminimizes or is substantially free from conventional surfactants such asPolysorbate 80 and Polysorbate 20.

SUMMARY

Disclosed herein, in embodiments, are therapeutic formulationscomprising a protein active ingredient and a stabilizing excipient. Inembodiments, the formulation contains less than about 1 mg/mL of theprotein active ingredient, or between about 1 μg/mL and about 1 mg/mL ofprotein active ingredient, or at least about 1 mg/mL of protein activeingredient, or at least about 5 mg/mL of protein active ingredient, orat least 100 mg/mL of protein active ingredient, or at least about 200mg/mL of protein active ingredient, or at least about 300 mg/mL ofprotein active ingredient. In embodiments, the protein active ingredientis selected from the group consisting of an antibody, an antibody-drugconjugate, an enzyme, a cytokine, a neurotoxin, a fusion protein, animmunogenic protein, a PEGylated protein, and an antibody fragment. Inembodiments, the formulation contains at least about 1 to about 5000 ppmof the stabilizing excipient, or at least about 1 to about 500 ppm ofthe stabilizing excipient, or at least about 10 to about 100 ppm of thestabilizing excipient. In embodiments, the stabilizing excipientexcludes polypropylene block copolymers.

In certain embodiments, the stabilizing excipient is selected from thegroup consisting of polypropylene glycol, adducts of polypropyleneglycol, and random copolymers comprising propylene oxide units. Thestabilizing excipient can be a polypropylene glycol homopolymer, and itcan have a number-average molecular weight between about 300 and 5000Daltons, or a number-average molecular weight of about 425 Daltons, ofabout 1000 Daltons, or of about 2000 Daltons. In embodiments, thepolypropylene glycol homopolymer is a linear polymer with at least twohydroxyl groups, which can contain two or three hydroxyl groups. Inembodiments, the polypropylene glycol is a branched polymer, and thebranched polymer can be formed by addition of propylene glycol units toa branched or multifunctional alcohol or a branched or multifunctionalamine. The branched or multifunctional alcohol can be a sugar, glycerol,pentaerythritol, or triethanolamine. In embodiments, the stabilizingexcipient is an adduct of polypropylene glycol. The adduct ofpolypropylene glycol can be a reaction product between propylene oxideand an alcohol or between propylene oxide and an amine. In certainembodiments, the stabilizing excipient is a hydrophobically modifiedcellulosic polymer. The hydrophobically modified cellulosic polymer canbe selected from the group consisting of a methylcellulose, ahydroxypropyl methylcellulose, a hydroxypropyl cellulose, and ahydroxyethyl cellulose. In embodiments, the hydrophobically modifiedcellulosic polymer is not a sodium carboxymethyl cellulose. In certainembodiments, the stabilizing excipient is a polyvinyl alcohol, which canhave a molecular weight between about 500 and about 500,000 Daltons,and/or which can have a hydrolysis percent between about 50% and about100%. In certain embodiments, the stabilizing excipient is apolyoxazoline, which can be selected from the group consisting ofpoly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline) andpoly(2-propyl-2-oxazoline). In embodiments, the polyoxazoline ispoly(2-ethyl-2-oxazoline). In embodiments, the polyoxazoline has aweight-average molecular weight between about 1000 and about 500,000Daltons, or a weight-average molecular weight between about 5000 andabout 50,000 Daltons. In certain embodiments, the stabilizing excipientis polyvinylpyrrolidone, which can have a molecular weight between about1000 and about 1,500,000 Daltons, or a molecular weight between about5000 and about 200,000 Daltons, or a molecular weight between about10,000 and about 100,000 Daltons.

In embodiments, the formulations disclosed herein can further comprise asecond stabilizing excipient. In embodiments, the formulation canexclude conventional surfactants. In other embodiments, the formulationfurther comprises between about 1 and about 5000 ppm of a conventionalsurfactant, or it comprises between about 1 and about 100 ppm of theconventional surfactant, or it comprises between about 10 and about 5000ppm of the conventional surfactant, or it comprises between about 100and 2000 ppm of the conventional surfactant, or it comprises betweenabout 100 and about 2000 ppm of the conventional surfactant. In otherembodiments, the formulation further comprises an additional agentselected from the group consisting of preservatives, sugars,polysaccharides, arginine, proline, hyaluronidase, stabilizers, andbuffers.

Also disclosed herein, in embodiments, are methods of improvingstability in a therapeutic formulation comprising a protein activeingredient by adding a stability-improving amount of a stabilizingexcipient to the therapeutic formulation. In embodiments, thestabilizing excipient reduces degradation of the therapeutic formulationby at least 10%, as compared to a control formulation lacking thestabilizing excipient, or the stabilizing excipient reduces degradationof the therapeutic formulation by at least 30%, as compared to a controlformulation lacking the stabilizing excipient, or the stabilizingexcipient reduces degradation of the therapeutic formulation by at least50%, as compared to a control formulation lacking the stabilizingexcipient, or the stabilizing excipient reduces degradation of thetherapeutic formulation by at least 70%, as compared to a controlformulation lacking the stabilizing excipient. Also disclosed herein, inembodiments, are methods of reducing adverse infusion-related effects ina patient, comprising administering to a patient in need thereof atherapeutic formulation comprising a protein active ingredient and astabilizing excipient, wherein infusing the therapeutic formulation intothe patient results in fewer adverse infusion-related effects thaninfusing a control formulation into the patient, wherein the controlformulation lacks the stabilizing excipient. In embodiments, the adverseinfusion-related effects are selected from the group consisting ofadverse infusion reactions, adverse immunogenic responses, and decreasein half-life of a therapeutic protein in the therapeutic formulation.

DETAILED DESCRIPTION 1. Definitions

For the purpose of this disclosure, the term “protein” refers to asequence of amino acids (i.e., a polypeptide) typically having amolecular weight between about 1-3000 kiloDaltons (kDa). Polypeptideswith molecular weight of about 1 kDa or higher are considered to beproteins for the purposes of the invention. In some embodiments, themolecular weight of the protein is between about 50-200 kDa; in otherembodiments, the molecular weight of the protein is between about20-1000 kDa or between about 20-2000 kDa. As would be understood byskilled artisans, a polypeptide of sufficient chain length can have atertiary or quaternary structure, while shorter polypeptides can lack atertiary or quaternary structure. A wide variety of biopolymers areincluded within the scope of the term “protein.” For example, the term“protein” can refer to therapeutic or non-therapeutic proteins,including antibodies, aptamers, fusion proteins, Fc fusion proteins,PEGylated proteins, synthetic polypeptides, protein fragments,lipoproteins, enzymes, immunogenic proteins (e.g., as used in vaccines),structural peptides, peptide drugs, and the like.

Those proteins having therapeutic effects may be termed “therapeuticproteins”; formulations containing therapeutic proteins intherapeutically effective amounts may be termed “therapeuticformulations.” The therapeutic protein contained in a therapeuticformulation may also be termed its “protein active ingredient.”Typically, a therapeutic formulation comprises a therapeuticallyeffective amount of a protein active ingredient and an excipient, withor without other optional components.

As used herein, the term “therapeutic” includes both treatments ofexisting disorders and preventions of disorders. A “treatment” includesany measure intended to cure, heal, alleviate, improve, remedy, orotherwise beneficially affect the disorder, including preventing ordelaying the onset of symptoms and/or alleviating or amelioratingsymptoms of the disorder. The term “treatment” includes a prophylacticor therapeutic vaccine or other preventive intervention.

Those patients in need of a treatment include both those who alreadyhave a specific disorder, and those for whom the prevention of adisorder is desirable. A disorder is any condition that alters thehomeostatic wellbeing of a mammal, including acute or chronic diseases,or pathological conditions that predispose the mammal to an acute orchronic disease. Non-limiting examples of disorders include cancers,metabolic disorders (e.g., diabetes), allergic disorders (e.g., asthma),dermatological disorders, cardiovascular disorders, respiratorydisorders, hematological disorders, musculoskeletal disorders,inflammatory or rheumatological disorders, autoimmune disorders,gastrointestinal disorders, urological disorders, sexual andreproductive disorders, neurological disorders, infectious diseases, andthe like.

The term “mammal” for the purposes of treatment can refer to any animalclassified as a mammal, including humans, domestic animals, pet animals,farm animals, sporting animals, working animals, and the like. A“treatment” can therefore include both veterinary and human treatments.For convenience, the mammal undergoing such “treatment” can be referredto as a “patient.” In certain embodiments, the patient can be of anyage, including fetal animals in utero.

In embodiments, a treatment involves providing a therapeuticallyeffective amount of a therapeutic formulation to a mammal in needthereof. A “therapeutically effective amount” is at least the minimumconcentration of the therapeutic protein administered to the mammal inneed thereof, to effect a treatment of an existing disorder or aprevention of an anticipated disorder (either such treatment or suchprevention being a “therapeutic intervention”). Therapeuticallyeffective amounts of various therapeutic proteins that may be includedas active ingredients in the therapeutic formulation may be familiar inthe art; or, for therapeutic proteins discovered or applied totherapeutic interventions hereinafter, the therapeutically effectiveamount can be determined by standard techniques carried out by thosehaving ordinary skill in the art, using no more than routineexperimentation.

As non-limiting examples, therapeutic proteins can include mammalianproteins such as hormones and prohormones (e.g., insulin and proinsulin,synthetic insulin, insulin analogs, glucagon, calcitonin, thyroidhormones (T3 or T4 or thyroid-stimulating hormone), parathyroid hormone,gastrin, cholecystokinin, leptin, follicle-stimulating hormone,oxytocin, vasopressin, atrial natriuretic peptide, luteinizing hormone,growth hormone, growth hormone releasing factor, somatostatin, and thelike); clotting and anti-clotting factors (e.g., tissue factor, vonWillebrand's factor, Factor VIIIC, Factor VIII, Factor IX, protein C,plasminogen activators (urokinase, tissue-type plasminogen activators),thrombin); cytokines, chemokines, and inflammatory mediators (e.g.,tumor necrosis factor inhibitors); interferons; colony-stimulatingfactors; interleukins (e.g., IL-1 through IL-10); growth factors (e.g.,vascular endothelial growth factors, fibroblast growth factor,platelet-derived growth factor, transforming growth factor, neurotrophicgrowth factors, insulin-like growth factor, and the like); albumins;collagens and elastins; hematopoietic factors (e.g., erythropoietin,thrombopoietin, and the like); osteoinductive factors (e.g., bonemorphogenetic protein); receptors (e.g., integrins, cadherins, and thelike); surface membrane proteins; transport proteins; regulatoryproteins; antigenic proteins (e.g., a viral component that acts as anantigen, as for example in a vaccine). A therapeutic protein can also bean immunogenic or other protein (including polypeptide) that is used asa vaccine, where a vaccine is a natural or synthetic preparation thatinduces acquired immunity to a disease. Therapeutic formulations used asvaccines include toxoid vaccines, protein-based or protein subunit-basedvaccines, or conjugate vaccines. As an illustrative, non-limitingexample, vaccines can contain a surface protein of a virus or a subunitthereof, as in the HPV virus, the Hepatitis B virus, and the influenzavirus.

Therapeutic proteins used as vaccines may be derived from naturalsources, for example, polypeptides or polypeptide fragments derived frommicroorganisms such as fungi (e.g., Aspergillus, Candida species),bacteria (e.g., Escherichia spp., Staphylococci spp., Streptococcispp.), protozoa such as sporozoa (e.g., Plasmodia), rhizopods (e.g.,Entamoeba) and flagellates (Trypanosoma, Leishmania, Trichomonas,Giardia, etc.), and viruses, such as (+) RNA viruses, (−) RNA viruses,dsDNA viruses, RNA to DNA viruses, and DNA to RNA viruses. Examples ofviruses from which vaccines are derived include without limitationPoxviruses (e.g., vaccinia), Picornaviruses (e.g., polio), Togaviruses(e.g., rubella), Flaviviruses (e.g., HCV); Coronaviruses, Rhabdoviruses(e.g., VSV); Paramyxovimses (e.g., RSV); Orthomyxovimses (e.g.,influenza); Bunyaviruses; Arenaviruses, Reoviruses, retroviruses (e.g.,HIV, HTLV); and Hepatitis B virus.

The term “therapeutic protein” includes, without limitation, the fullcomplement of proteins that can be used as drugs, for example, fusionproteins such as etanercept, denileukin diftitox, alefacept, abatacept,rinolacept, romiplostim, corifollitropin-alpha, belatacept, aflibercept,ziv-aflibercept, eftrenonacog-alpha, albiglutide, efraloctocog-alpha,dulaglutide, and the like.

The term “therapeutic protein” also includes antibodies. The term“antibody” is used herein in its broadest sense, to include asnon-limiting examples monoclonal antibodies (including, for example,full-length antibodies with an immunoglobulin Fc region), single-chainmolecules, bi-specific and multi-specific antibodies, diabodies,antibody-drug conjugates, antibody compositions having polyepitopicspecificity, and fragments of antibodies (including, for example, Fab,Fv, Fc, and F(ab′)2).

Antibodies can also be termed “immunoglobulins.” An antibody isunderstood to be directed against a specific protein or non-protein“antigen,” which is a biologically important material; theadministration of a therapeutically effective amount of an antibody to apatient can complex with the antigen, thereby altering its biologicalproperties so that the patient experiences a therapeutic effect.

In embodiments, the proteins can be PEGylated, meaning that theycomprise polyethylene glycol (PEG) and/or polypropylene glycol (PPG)units. PEGylated proteins, or PEG-protein conjugates, have found utilityin therapeutic applications due to their beneficial properties such asimproved solubility, improved pharmacokinetics, improvedpharmacodynamics, less immunogenicity, lower renal clearance, andimproved stability. Non-limiting examples of PEGylated proteins arePEGylated interferons (PEG-IFN), PEGylated anti-VEGF, PEG proteinconjugate drugs, Adagen, Pegaspargase, Pegfilgrastim, Pegloticase,Pegvisomant, PEGylated epoetin-β, and Certolizumab pegol.

PEGylated proteins can be synthesized by a variety of methods such as areaction of protein with a PEG reagent having one or more reactivefunctional groups. The reactive functional groups on the PEG reagent canform a linkage with the protein at targeted protein sites such aslysine, histidine, cysteine, and the N-terminus. Typical PEGylationreagents have reactive functional groups such as aldehyde, maleimide, orsuccinimide groups that have specific reactivity with targeted aminoacid residues on proteins. The PEGylation reagents can have a PEG chainlength from about 1 to about 1000 PEG and/or PPG repeating units. Othermethods of PEGylation include glyco-PEGylation, where the protein isfirst glycosylated and then the glycosylated residues are PEGylated in asecond step. Certain PEGylation processes are assisted by enzymes likesialyltransferase and transglutaminase.

While the PEGylated proteins can offer therapeutic advantages overnative, non-PEGylated proteins, these materials can have physical orchemical properties that make them difficult to purify, dissolve,filter, concentrate, and administer. The PEGylation of a protein canlead to a higher solution viscosity compared to the native protein, andthis generally requires the formulation of PEGylated protein solutionsat lower concentrations.

Those proteins used for non-therapeutic purposes (i.e., purposes notinvolving treatments), such as household, nutrition, commercial, andindustrial applications, may be termed “non-therapeutic proteins.”Formulations containing non-therapeutic proteins may be termed“non-therapeutic formulations”. The non-therapeutic proteins can bederived from plant sources, animal sources, or produced from cellcultures; they also can be enzymes or structural proteins. Thenon-therapeutic proteins can be used in in household, nutrition,commercial, and industrial applications such as catalysts, human andanimal nutrition, processing aids, cleaners, and waste treatment.

An important category of non-therapeutic biopolymers includes enzymes.Enzymes have a number of non-therapeutic applications, for example, ascatalysts, human and animal nutritional ingredients, processing aids,cleaners, and waste treatment agents. Enzyme catalysts are used toaccelerate a variety of chemical reactions. Examples of enzyme catalystsfor non-therapeutic uses include catalases, oxidoreductases,transferases, hydrolases, lyases, isomerases, and ligases. Human andanimal nutritional uses of enzymes include nutraceuticals, nutritivesources of protein, chelation or controlled delivery of micronutrients,digestion aids, and supplements; these can be derived from amylase,protease, trypsin, lactase, and the like. Enzymatic processing aids areused to improve the production of food and beverage products inoperations like baking, brewing, fermenting, juice processing, andwinemaking. Examples of these food and beverage processing aids includeamylases, cellulases, pectinases, glucanases, lipases, and lactases.Enzymes can also be used in the production of biofuels. Ethanol forbiofuels, for example, can be aided by the enzymatic degradation ofbiomass feedstocks such as cellulosic and lignocellulosic materials. Thetreatment of such feedstock materials with cellulases and ligninasestransforms the biomass into a substrate that can be fermented intofuels. In other commercial applications, enzymes are used as detergents,cleaners, and stain lifting aids for laundry, dish washing, surfacecleaning, and equipment cleaning applications. Typical enzymes for thispurpose include proteases, cellulases, amylases, and lipases. Inaddition, non-therapeutic enzymes are used in a variety of commercialand industrial processes such as textile softening with cellulases,leather processing, waste treatment, contaminated sediment treatment,water treatment, pulp bleaching, and pulp softening and debonding.Typical enzymes for these purposes are amylases, xylanases, cellulases,and ligninases.

Other examples of non-therapeutic biopolymers include fibrous orstructural proteins such as keratins, collagen, gelatin, elastin,fibroin, actin, tubulin, or the hydrolyzed, degraded, or derivatizedforms thereof. These materials are used in the preparation andformulation of food ingredients such as gelatin, ice cream, yogurt, andconfections; they area also added to foods as thickeners, rheologymodifiers, mouthfeel improvers, and as a source of nutritional protein.In the cosmetics and personal care industry, collagen, elastin, keratin,and hydrolyzed keratin are widely used as ingredients in skin care andhair care formulations. Still other examples of non-therapeuticbiopolymers are whey proteins such as beta-lactoglobulin,alpha-lactalbumin, and serum albumin. These whey proteins are producedin mass scale as a byproduct from dairy operations and have been usedfor a variety of non-therapeutic applications.

As used herein, the term “conventional surfactant” refers to an organicsurface-active agent capable of lowering the surface tension between twoliquids, or lowering the interfacial tension between a liquid and asolid. A conventional surfactant is typically amphiphilic, and caninclude a hydrophilic “head” and one or two hydrophobic “tails.” Thecharged character of the head group allows categorization of theconventional surfactant: a surfactant with a positively-charged head istermed cationic; a surfactant with a negatively-charged head is termedanionic; a surfactant with no charged groups on its head is termednon-ionic; and a surfactant having a head with two oppositely chargedgroups is termed zwitterionic. The tail of the conventional surfactantcan comprise a branched, linear, or aromatic hydrocarbon chain, or itcan comprise a fluorocarbon chain (for fluorosurfactants), or a siloxanechain (for siloxane surfactants). The hydrophilic properties of aconventional surfactant can be increased by including ethoxylatedsequences (e.g. polyethylene oxide), while the lipophilic properties ofthe conventional surfactant can be increased by including polypropyleneoxide sequences.

In embodiments, the conventional surfactant can be a polysorbate, i.e.,an emulsifier derived from an ethoxylated sorbitan ester of a fattyacid. For example, Polysorbate 20 (polyoxyethylene (20) sorbitanmonolaurate) and Polysorbate 80 (polyoxyethylene (20) sorbitanmonooleate) are commonly used as conventional surfactants for proteinformulations. In other embodiments, the conventional surfactant can bean ethoxylated fatty alcohol, a diblock copolymer of ethylene oxide (EO)and propylene oxide (PO), or a triblock copolymer of EO and PO.

2. General

The present disclosure relates to aqueous formulations of therapeuticproteins with stabilizing excipients. As used herein, the term“stabilizing excipient” refers to an excipient that reduces thedegradation of a therapeutic protein in response to a stress condition.A stress condition can be any condition that alters the proteinstructure, for example, by causing greater protein unfolding, leading toaccelerated aggregation and degradation of the protein formulation.Stress conditions can include, without limitation, agitation,filtration, freeze/thaw conditions, lyophilization, exposure to storagetemperatures above 5° C., or exposure to a liquid/air or liquid/solidinterface. Other mechanisms involved in stress conditions includeoxidation, hydrolysis, proteolysis, deamidation, disulfide scrambling,photodegradation, and microbial degradation.

It is well known to those skilled in the art of polymer science andengineering that proteins in solution tend to form entanglements, whichcan limit the translational mobility of the entangled chains andinterfere with the protein's therapeutic or nontherapeutic efficacy. Inembodiments, stabilizing excipient compounds as disclosed herein cansuppress protein clustering due to specific interactions between theexcipient compound and the therapeutic protein in solution.

In embodiments, the approaches disclosed herein can yield a liquidformulation having improved stability when compared to a traditionalprotein solution. A stable formulation is one in which the proteincontained therein substantially retains its physical and chemicalstability and its therapeutic or nontherapeutic efficacy upon storageunder storage conditions, whether cold storage conditions, roomtemperature conditions, or elevated temperature storage conditions.Advantageously, a stable formulation can also offer protection againstaggregation or precipitation of the proteins dissolved therein. Forexample, the cold storage conditions can entail storage in arefrigerator or freezer. In some examples, cold storage conditions canentail conventional refrigerator or freezer storage at a temperature of10° C. or less. In additional examples, the cold storage conditionsentail storage at a temperature from about 2° to about 10° C. In otherexamples, the cold storage conditions entail storage at a temperature ofabout 4° C. In additional examples, the cold storage conditions entailstorage at freezing temperature such as about 0° C. or lower. In anotherexample, cold storage conditions entail storage at a temperature ofabout −30° C. to about 0° C. The room temperature storage conditions canentail storage at ambient temperatures, for example, from about 10° C.to about 30° C. Elevated temperature stability, for example, attemperatures from about 30° C. to about 50° C., can be used as part ofan accelerated aging study to predict the long term storage at typicalambient (10-30° C.) conditions.

In embodiments, advantageous stabilizing excipients can comprisepropylene glycol, polypropylene glycol homopolymers, adducts ofpolypropylene glycol, or random copolymers comprising propylene oxideunits. In other embodiments, the stabilizing excipients can comprise ahydrophobically modified cellulose, which can be a methylcellulose, ahydroxypropyl methylcellulose, a hydroxypropyl cellulose, or ahydroxyethyl cellulose, and is not a sodium carboxy methylcellulose. Inother embodiments, the stabilizing excipient is polyvinyl alcohol. Inother embodiments, the stabilizing excipient is a polyoxazoline, such aspoly(2-ethyl-2-oxazoline). In other embodiments, the stabilizingexcipient is polyvinyl pyrrolidone.

For example, in embodiments, the stabilizing excipients can comprise apolypropylene glycol (PPG) homopolymer with a number-average molecularweight (M_(n)) between 300 and 5000 Daltons (Da), such as PPG425,PPG1000, and PPG2000. In embodiments, the stabilizing excipients cancomprise a PPG/PEG copolymer with up to 50% of polyethylene glycol (PEG)repeating units. A PPG excipient can be a linear polymer with two orthree terminal hydroxyl groups. In embodiments, the stabilizingexcipients can comprise a polypropylene glycol (PPG) adduct, such as areaction product between propylene glycol and an alcohol group or anamine group. In embodiments, the PPG excipient can be in the form of abranched polymer formed by addition of propylene glycol units to abranched or multifunctional alcohol or amine like glycerol,triethanolamine, a sugar, or pentaerythritol.

In embodiments, the stabilizing excipient can comprise a hydrophobicallymodified cellulose such as hydroxypropyl methylcellulose,methylcellulose, hydroxypropyl cellulose, or hydroxyethyl cellulose. Lowmolecular weight hydroxypropyl methylcellulose (HPMC) and low molecularweight methylcellulose (MC) are commercially available under thetrademark METHOCEL® from Dow Chemical Company (Midland, Mich.). Thenaming convention for the Methocel product line is such that the numberin the product name is the viscosity of a 2% solution in water, “LV”stands for low viscosity, and the first letter indicates the type (HPMCor MC) and degree of substitution. Low molecular weight HPMC productssuch as Methocel E3LV, Methocel E15LV and Methocel K3LV and lowmolecular weight MC products (e.g. Methocel A15LV) can be used asstabilizing excipients.

In embodiments, the stabilizing excipient can comprise a polyvinylalcohol that is prepared from polyvinyl acetate with a molecular weightbetween 5000 and 500,000 Da and a degree of hydrolysis between 50% and100%. In embodiments, the polyvinyl alcohol has a degree of hydrolysisfrom 80% to about 99%, or from about 83% to about 95%. In embodiments,the polyvinyl alcohol has a molecular weight between about 10,000 andabout 100,000 Da. In embodiments, the polyvinyl alcohol has a 4% aqueoussolution viscosity at 20-25° C. in the range of about 3 to about 50 cP.In embodiments, the polyvinyl alcohol is a United States Pharmacopeia(USP) grade.

In embodiments, the stabilizing excipient can comprise apolyvinylpyrrolidone (PVP). The PVP excipient can have a molecularweight of about 1000 to about 1.5 million Da. In embodiments, the PVPstabilizing excipient can have a molecular weight of about 5000 to about200,000 Da. In embodiments, the PVP stabilizing excipient can have amolecular weight of about 10,000 to about 100,000 Da.

In embodiments, the stabilizing excipient can comprise a polyoxazolinesuch as poly(2-methyl-2-oxazoline), poly(2-ethyl-2-oxazoline) orpoly(2-propyl-2-oxazoline). In embodiments, the stabilizingpolyoxazoline excipient can have a number-average molecular weight of1,000 to 500,000 Da or 5,000 to 50,000 Da.

The stabilizing excipient can be added alone, or in combination withconventional surfactants such as nonionic surfactants such asPolysorbate 80, Polysorbate 20 and the like. When a stabilizingexcipient is combined with a conventional surfactant excipient, a lesseramount of conventional excipient may be required, for example. 0-100 ppmof the conventional surfactant, or 100-2000 ppm of the conventionalsurfactant. In other embodiments, the therapeutic protein formulationcontains the stabilizing excipient and an amount of 10-5000 ppm of aconventional surfactant. In embodiments, the stabilizing excipient isadded to the formulation in amounts ranging from 10-5000 ppm. Inembodiments, the stabilizing excipient is added to the formulation inamounts ranging from 100-1000 ppm. Reducing the amounts of conventionalsurfactant in a therapeutic formulation can offer certain advantagessuch as improved formulation stability, improved excipient stability,and reduced foaming tendency. In embodiments, solutions of therapeuticproteins containing the stabilizing excipients of the invention can havea lower foaming tendency compared with solutions of the same therapeuticproteins without the stabilizing excipients.

Advantageously, the stabilizing excipients can be selected so that theydo not form micelles in aqueous solution and they can pass through anultrafiltration membrane. Advantageously, the stabilizing excipients canbe selected so that they do not increase the foaming tendency of theformulation. Advantageously, the stabilizing excipients can be selectedso that they do not include conventional amphiphilic surfactantstructures. In embodiments, the stabilizing excipients can be selectedso that they are not structured as having a hydrophilic head and ahydrophobic tail. In other embodiments, the stabilizing excipients canbe selected so that they do not comprise block copolymers, for example,so that block copolymer arrangements such as the (propyleneoxide-co-ethylene oxide) copolymer configurations of PO/EO/PO, EO/PO orEO/PO/EO are excluded. In embodiments, stabilizing excipients can beselected that are free of ethylene oxide (EO) groups, residual ethyleneoxide monomer, and/or dioxane byproducts. In embodiments, thestabilizing excipients are selected so that they contain no esterlinkages. In embodiments, the stabilizing excipients are purified tominimize the presence of endotoxins or heavy metals. In embodiments, thestabilizing excipients are USP grade materials. Stabilizing excipientcompounds as disclosed herein can be natural or synthetic, and, incertain embodiments they may be substances that the U.S. FDA generallyrecognizes as safe (GRAS), or that are well established and commonlyused in registered drug products such as are usually included inpharmacopoeias, or that are included in a registry or database such asthe FDA's Inactive Ingredient Database(https://www.accessdata.fda.gov/scripts/cder/iig/).

3. Therapeutic Formulations

In one aspect, the formulations and methods disclosed herein providestable liquid formulations, comprising a therapeutic protein in atherapeutically effective amount and a stabilizing excipient compound.In embodiments, the formulation can improve the stability whileproviding an acceptable concentration of active ingredients and anacceptable stability. In embodiments, the formulation provides animprovement in stability when compared to a control formulation; for thepurposes of this disclosure, a control formulation is a formulationcontaining the protein active ingredient that is identical on a dryweight basis in every way to the therapeutic formulation except that itlacks the excipient compound. In embodiments, improved stability of theprotein containing formulation is indicated by a lower percentage ofsoluble aggregates, a lower percentage of fragments, a decrease in thenumber of particulates, a decrease in the number of subvisibleparticles, a decrease in the hydrodynamic particle size, or thesuppression of gel formation, as compared to a control formulation aftera stress condition. In embodiments, the stress conditions can includefreeze/thaw cycles, exposure to storage conditions for >1 month atfreezing temperatures (below 0° C.), exposure to storage conditionsfor >1 month at refrigerated temperatures (between 0° C. and 15° C.),exposure to storage conditions for >1 month at ambient temperatures(between 15° C. and 30° C.), exposure to storage conditions for >1 weekat elevated temperatures (between 30° C. and 100° C.), exposure toagitation stress, exposure to air/water interfaces, contact withplastic, glass, or metal surfaces, filtration, column chromatographyseparation, viral inactivation, exposure to pH conditions between pH 2and pH 5, exposure to pH conditions between pH 8 and pH 12, exposure toproteolytic enzymes, exposure to lipase enzymes, or exposure tomicrobiological contamination.

It is understood that the stability of a liquid protein formulation canbe affected by a variety of factors, including, but not limited to: thenature of the protein itself (e.g., enzyme, antibody, receptor, fusionprotein, etc.); its size, three-dimensional structure, chemicalcomposition, and molecular weight; its concentration in the formulation;the components of the formulation besides the protein; the formulationpH range; the storage conditions for the formulation; and the method ofadministering the formulation to the patient. Therapeutic proteins mostsuitable for use with the excipient compounds described herein arepreferably essentially pure, i.e., free from contaminating proteins. Inembodiments, an “essentially pure” therapeutic protein is a proteincomposition comprising at least 90% by weight of the therapeuticprotein, or preferably at least 95% by weight, or more preferably, atleast 99% by weight, all based on the total weight of therapeuticproteins and contaminating proteins in the composition. For the purposesof clarity, a protein added as an excipient is not intended to beincluded in this definition. The therapeutic formulations describedherein are intended for use as pharmaceutical-grade formulations, i.e.,formulations intended for use in treating a mammal, in such a form thatthe desired therapeutic efficacy of the protein active ingredient can beachieved, and without containing components that are toxic to the mammalto whom the formulation is to be administered.

In embodiments, the therapeutic formulation contains at least 1 μg/mL ofprotein active ingredient. In embodiments, the therapeutic formulationcontains between about 1 μg/mL and about 1 mg/mL of protein activeingredient. In embodiments, the therapeutic formulation contains atleast 1 mg/mL of protein active ingredient. In embodiments, thetherapeutic formulation contains at least 5 mg/mL of protein activeingredient. In other embodiments, the therapeutic formulation containsat least 100 mg/mL of protein active ingredient. In other embodiments,the therapeutic formulation contains at least 200 mg/mL of proteinactive ingredient. In yet other embodiments, the therapeutic formulationsolution contains at least 300 mg/mL of protein active ingredient.Generally, the excipient compounds disclosed herein are added to thetherapeutic formulation in an amount between about 1 to about 5000 ppm.In embodiments, the excipient compound can be added in an amount ofabout 1 to about 500 ppm. In embodiments, the excipient compound can beadded in an amount of about 10 to about 100 ppm.

In embodiments, the excipient compounds disclosed herein are added tothe therapeutic formulation in a stability-improving amount. Inembodiments, a stability-improving amount is the amount of an excipientcompound that reduces the degradation of the formulation by at least 10%when compared to a control formulation; for the purposes of thisdisclosure, a control formulation is a formulation containing theprotein active ingredient that is identical on a dry weight basis inevery way to the therapeutic formulation except that it lacks theexcipient compound. In embodiments, the stability-improving amount isthe amount of an excipient compound that reduces the degradation of theformulation by at least 30% when compared to the control formulation. Inembodiments, the stability-improving amount is the amount of anexcipient compound that reduces the degradation of the formulation by atleast 50% when compared to the control formulation. In embodiments, thestability-improving amount is the amount of an excipient compound thatreduces the degradation of the formulation by at least 70% when comparedto the control formulation. In embodiments, the stability-improvingamount is the amount of an excipient compound that reduces thedegradation of the formulation by at least 90% when compared to thecontrol formulation.

Therapeutic formulations in accordance with this disclosure have certainadvantageous properties. In embodiments, the therapeutic formulationsare resistant to shear degradation, phase separation, clouding out,precipitation, and denaturing. In embodiments, the therapeuticformulations are processed, purified, stored, syringed, dosed, filtered,and centrifuged more effectively, compared with a control formulation.In embodiments, the therapeutic formulations can result in fewer adverseinfusion-related effects, for example, adverse infusion reactions,adverse immunogenic responses, decrease in half-life of a therapeuticprotein in the therapeutic formulation, and the like. In embodiments,when the therapeutic formulations are administered to patients, they canexperience fewer infusion reactions than would be experienced with asimilar formulation lacking the stabilizing excipient. In embodiments,when the therapeutic formulations are administered to patients, they canexperience fewer or less intense immunogenic responses than would beexperienced with a similar formulation lacking the stabilizingexcipient. In embodiments, when the therapeutic formulations areadministered to patients, they can experience less decrease in thehalf-life of the therapeutic protein in the body, as compared to asimilar formulation lacking the stabilizing excipient.

In embodiments, the stabilizing excipient has antioxidant propertiesthat stabilize the therapeutic protein against oxidative damage. Inembodiments, the therapeutic formulation is stored at ambienttemperatures, or for extended time at refrigerator conditions withoutappreciable loss of potency for the therapeutic protein. In embodiments,the therapeutic formulation is dried down for storage until it isneeded; then it is reconstituted with an appropriate solvent, e.g.,water. Advantageously, the formulations prepared as described herein canbe stable over a prolonged period of time, from months to years. Whenexceptionally long periods of storage are desired, the formulations canbe preserved in a freezer (and later reactivated) without fear ofprotein denaturation. In embodiments, formulations can be prepared forlong-term storage that do not require refrigeration. In embodiments, thestabilizing excipient can be used to improve solubility or stability ofprotein therapeutics that have limited water solubility, such asantibody-drug conjugates.

In embodiments, the stabilizing excipient provides a substitute for someor all of the conventional surfactants that are employed in proteinformulations, as described previously. As described previously, thestabilizing excipient can be added to a protein formulation alone or incombination with one or more other excipients, either to replace theconventional surfactant in the formulation entirely, or to reduce theamount of the conventional surfactant that is used. In embodiments, thestabilizing excipient is not an ethoxylated compound, and does notcontain residual amounts of 1,4-dioxane.

Methods for preparing therapeutic formulations may be familiar toskilled artisans. The therapeutic formulations of the present inventioncan be prepared, for example, by adding the stabilizing excipientcompound to the formulation before or after the therapeutic protein isadded to the solution. The therapeutic formulation can, for example, beproduced by combining the therapeutic protein and the excipient at afirst (lower) concentration and then processed by filtration orcentrifugation to produce a second (higher) concentration of thetherapeutic protein. Therapeutic formulations can be made with one ormore of the excipient compounds with chaotropes, kosmotropes,hydrotropes, and salts. Therapeutic formulations can be made with one ormore of the excipient compounds using techniques such as encapsulation,dispersion, liposome, vesicle formation, and the like. Methods forpreparing therapeutic formulations comprising the stabilizing excipientcompounds disclosed herein can include combinations of the excipientcompounds. Other additives may be introduced into the therapeuticformulations during their manufacture, including preservatives,conventional surfactants, sugars, sucrose, trehalose, polysaccharides,arginine, proline, hyaluronidase, stabilizers, buffers, and the like. Asused herein, a pharmaceutically acceptable stabilizing excipientcompound is one that is non-toxic and suitable for animal and/or humanadministration.

4. Protein/Excipient Formulations: Properties and Processes

In embodiments, certain of the above-described stabilizing excipientcompounds are used to improve a protein-related process, such as themanufacture, processing, sterile filling, purification, and analysis ofprotein-containing solutions, using processing methods such asfiltration, syringing, transferring, pumping, mixing, heating or coolingby heat transfer, gas transfer, centrifugation, chromatography, membraneseparation, centrifugal concentration, tangential flow filtration,radial flow filtration, axial flow filtration, lyophilization, and gelelectrophoresis. These processes and processing methods can haveimproved efficiency due to the improved stability of the proteins in thesolution during manufacture, processing, purification, and analysissteps. In embodiments, the stabilizing excipient can be added to aprotein-containing solution before a concentration step, and thestabilizing excipient can improve the efficiency, throughput, or yieldof the concentration step. In embodiments, the stabilizing excipientdoes not become concentrated with the protein phase during afiltration-based concentration step. In embodiments, the stabilizingexcipient does not form micelles when added to a protein-containingsolution. Additionally, equipment-related processes such as the cleanup,sterilization, and maintenance of protein processing equipment can befacilitated by the use of the above-identified excipients due todecreased fouling, decreased denaturing, lower viscosity, and improvedsolubility of the protein.

EXAMPLES

As used herein, the term wt % refers to percentage on a weight basis.

Example 1: Agitation Stress of ERBITUX® Formulations

This example compares the effect of the following stabilizing excipientsin ERBITUX® formulations that were subjected to agitation stresses:polypropylene glycol, M_(n) ˜425 g/mol (PPG425), polypropylene glycol,M_(n) ˜1000 g/mol (PPG1000), polypropylene glycol, M_(n) ˜2000 g/mol(PPG2000), polyethylene glycol, M_(n) ˜1000 g/mol (PEG1000). Allstabilizing excipient reagents were obtained from Sigma-Aldrich, St.Louis, Mo.

An ERBITUX® formulation was prepared as follows. A commercial cetuximab(ERBITUX®) drug product distributed in the U.S. by Eli Lilly & Co. wasacquired. According to the FDA drug label, the commercial formulationcontained 2 mg/mL cetuximab, 8.48 mg/mL sodium chloride, 1.88 mg/mLsodium phosphate dibasic heptahydrate and 0.41 mg/mL sodium phosphatemonobasic monohydrate.

The ERBITUX® sample was then reformulated in 15 mM sodium phosphate and4.8 mg/mL sodium chloride at pH 7 in the presence of about 200 ppm of astabilizing excipient in the following way. Buffer solutions wereprepared by dissolving approximately 0.1 g sodium phosphate monobasicdihydrate (Sigma-Aldrich, St. Louis, Mo.), 0.24 g sodium chloride(Sigma-Aldrich, St. Louis, Mo.) and about 0.1 g of the desiredstabilizing excipient in deionized water, and diluted to a final mass ofabout 50 g with additional deionized water. The solution pH of eachbuffer was adjusted to about 7 with the dropwise addition of either 5 Msodium hydroxide or 1 M sodium hydroxide. Buffers were filtered through0.2 micron sterile polyethersulfone syringe filter (GE HealthcareBiosciences, Pittsburgh, Pa.), and 0.4 mL of each buffer added tosterile 5 mL polypropylene tubes along with about 3.4 mL of the samebuffer containing no excipient. In this way, a final excipientconcentration of about 200 ppm was achieved in each sample. Amicon Ultra15 centrifugal concentrator tubes with a 30 kDa nominal molecular weightcut-off (EMD-Millipore, Billerica, Mass.) were rinsed with deionizedwater, filled with 13 mL of Erbitux sample, and centrifuged in a SorvallLegend RT centrifuge for about 25 minutes at about 3200×g and 25° C. toa final retentate volume of about 1 mL or a concentration of about 30mg/mL cetuximab. The filtrate was then removed and about 0.26 mL wasadded to each buffer containing 5 mL sterile polypropylene tube,filtered through 0.2 micron sterile syringe filters.

The resulting cetuximab formulations in the 5 mL polypropylene tubes,having a concentration of about 2 mg/mL cetuximab and final volume ofabout 4 mL, were placed on a Daigger Scientific (Vernon Hills, Ill.)Labgenius orbital shaker at 275 rpm for agitation stressing. After about16 hours and about 40 hours of continuous shaking at ambienttemperature, samples were pulled and analyzed by optical absorbance in aThermo Fisher Scientific Evolution spectrophotometer with a 10 mm pathlength cuvette, and by dynamic light scattering (DLS) with a ZetaPlusfrom Brookhaven Instruments (Holtsville, N.Y.).

Absorbance at 350 nm and 550 nm was utilized as a measurement ofturbidity, with higher absorbance indicating more degradation of thecetuximab after stress, due to the formation of more insolubleparticulates. Absorbance values are reported in Absorbance Units (AU)from the spectrophotometer measurements. The results are presented inTable 1 below, showing absorbance values measured after 0, 16, and 40hours of agitation.

Dynamic light scattering (DLS) measurements yielded an effectivediameter in nanometers and were not corrected for slight differences inviscosity and refractive index of the buffers. Instead, the DLSmeasurements were used as a more sensitive way than turbidity formonitoring protein aggregation. The DLS results are summarized in Table2.

TABLE 1 Absorbance Absorbance Stabilizing at 350 nm (AU) at 550 nm (AU)excipient 0 hrs 16 hrs 40 hrs 0 hrs 16 hrs 40 hrs PEG1000 −0.01 0.000.01 −0.02 −0.01 −0.01 PPG425 −0.01 −0.03 −0.04 −0.02 −0.03 −0.04PPG1000 −0.03 −0.02 0.00 −0.03 −0.02 0.00 PPG2000 −0.04 −0.03 −0.01−0.04 −0.03 −0.01 None −0.01 0.91 1.62 −0.01 0.52 0.96

TABLE 2 Stabilizing DLS effective diameter (nm) excipient 0 hrs 16 hrs40 hrs PEG1000 11.6 14.2 2900 PPG425 11.8 12.0 11.8 PPG1000 11.8 11.511.7 PPG2000 11.6 12.2 12.1 None 11.6 1729 1248

The four formulations containing a stabilizing excipient all performedsubstantially better than the control formulation (which used the samebuffer with no excipient). There was no significant difference in lightabsorbance measurements for the four formulations containing excipient.However, DLS measurements of effective particle diameter indicatedaggregate formation in the sample containing PEG1000, while the samplescontaining PPG did not show any signs of aggregation, regardless ofmolecular weight within the range tested in this example. Therefore, incan be concluded that the various PPG excipients are more effective inpreventing degradation of protein solutions due to agitation and/orexposure to air/liquid interfaces than PEG1000.

Example 2: FlowCAM Particle Analysis of Stressed Cetuximab Formulations

Samples containing about 2 mg/mL cetuximab in phosphate buffer at pH 7with 200 ppm excipient, prepared in accordance with Example 1, wereanalyzed for insoluble particles by dynamic flow imaging with a FlowCamVS1 (Fluid Imaging Technologies, Scarborough, Me.). The FlowCam wasequipped with a 20× objective lens and a 50 micron depth flow cell, andoperated at a flow rate of 0.03 mL/min. Measurements were made intriplicate using a sample volume of 0.2 mL per run. Particles werecounted and grouped into four categories by equivalent sphericaldiameter using the VisualSpreadsheet particle analysis software providedwith the FlowCam instrument, and each particle class averaged for thethree sample runs. The results of the experiment are presented in Table3 below. Particle analysis by FlowCam further demonstrated the greaterstabilization achieved with PPG excipients than the PEG1000. Within thePPG samples, PPG1000 and PPG2000 performed similarly and yieldedslightly lower particle counts than the sample with PPG425 as theexcipient.

TABLE 3 Average number of particles per mL after 40 hours shaking: 2-10μm 10-20 μm 20-50 μm >50 μm particles particles particles particlesStabilizing St. St. St. St. excipient Avg. Dev. Avg. Dev. Avg. Dev. Avg.Dev. PEG1000 129445 14028 18474 988 9055 1174 1390 119 PPG425 2119 841281 139 118 42 22 15 PPG1000 416 103 31 0 0 0 0 0 PPG2000 187 155 21 150 0 0 0

Example 3: Evaluation of Low Molecular Weight Hydrophobically ModifiedCellulose

Low molecular weight hydroxypropyl methylcellulose (HPMC) and lowmolecular weight methylcellulose (MC) are hydrophobically modifiedcellulose polymers that are commercially available under the trademarkMETHOCEL® from Dow Chemical Company (Midland, Mich.). The namingconvention for the METHOCEL® product line is such that the number in theproduct name is the viscosity of a 2% solution in water, “LV” stands forlow viscosity, and the first letter indicates the type (HPMC or MC) anddegree of substitution. Three low molecular weight HPMC products(Methocel E3LV, Methocel E15LV and Methocel K3LV) and one low molecularweight MC product (Methocel A15LV) were used as stabilizing excipientsin this Example along with Polysorbate 80 (PS80) and polypropyleneglycol 2000 (PPG2000) which were obtained from Sigma-Aldrich, St. Louis,Mo.

An ERBITUX® formulation was prepared as follows. A commercial cetuximab(ERBITUX®) drug product distributed in the U.S. by Eli Lilly & Co. wasacquired. According to the FDA drug label, the commercial formulationcontained 2 mg/mL cetuximab, 8.48 mg/mL sodium chloride, 1.88 mg/mLsodium phosphate dibasic heptahydrate and 0.41 mg/mL sodium phosphatemonobasic monohydrate.

The Erbitux sample was then reformulated in 15 mM sodium phosphate and4.8 mg/mL sodium chloride at pH 7 in the presence of about 200 ppm of astabilizing excipient in the following way. Buffer solutions wereprepared by dissolving approximately 0.1 g sodium phosphate monobasicdihydrate (Sigma-Aldrich, St. Louis, Mo.), 0.24 g sodium chloride(Sigma-Aldrich, St. Louis, Mo.) and about 0.1 g of the desiredstabilizing excipient in deionized water, and diluted to a final mass ofabout 50 g with additional deionized water. The solution pH of eachbuffer was adjusted to about 7 with the dropwise addition of either 5 Msodium hydroxide or 1 M sodium hydroxide. Buffers were filtered through0.2 micron sterile polyethersulfone syringe filter (GE HealthcareBiosciences, Pittsburgh, Pa.), and 0.4 mL of each buffer added tosterile 5 mL polypropylene tubes along with about 3.4 mL of the samebuffer containing no excipient. In this way, a final excipientconcentration of about 200 ppm was achieved in each sample. Amicon Ultra15 centrifugal concentrator tubes with a 30 kDa nominal molecular weightcut-off (EMD-Millipore, Billerica, Mass.) were rinsed with deionizedwater, filled with 13 mL of Erbitux sample, and centrifuged in a SorvallLegend RT centrifuge for about 27 minutes at about 3200×g and 25° C. toa final retentate volume of about 0.6 mL or a concentration of about 40mg/mL cetuximab. The filtrate was then removed and about 0.2 mL wasadded to each buffer containing 5 mL sterile polypropylene tube,filtered through 0.2 micron sterile syringe filters.

The resulting cetuximab formulations in the 5 mL polypropylene tubes,having a concentration of about 2 mg/mL cetuximab and final volume ofabout 4 mL, were placed on a Daigger Scientific (Vernon Hills, Ill.)Labgenius orbital shaker at 275 rpm. After about 16 hours and about 40hours of continuous shaking at ambient temperature, samples were pulledand analyzed by light absorbance in a Thermo Fisher Scientific Evolutionspectrophotometer with a 10 mm path length cuvette, and by dynamic lightscattering (DLS) with a ZetaPlus from Brookhaven Instruments(Holtsville, N.Y.).

Absorbance at 350 nm and 550 nm was utilized as a measurement ofturbidity, with higher absorbance indicating more degradation of thecetuximab after stress, due to the formation of more insolubleparticulates. The absorbance results are reported in Absorbance Units(AU) from the spectrophotometer measurements and they are summarized inTable 4 below.

Dynamic light scattering measurements yielded an effective diameter innanometers and were not corrected for slight differences in viscosityand refractive index of the buffers. Instead, the DLS measurements wereused as a more sensitive way than turbidity for monitoring proteinaggregation. The dynamic light scattering results are summarized inTable 5 below.

TABLE 4 Absorbance Absorbance Stabilizing at 350 nm (AU) at 550 nm (AU)excipient 0 hrs 16 hrs 40 hrs 0 hrs 16 hrs 40 hrs Methocel K3LV −0.010.01 −0.08 −0.01 0.01 −0.09 Methocel E3LV −0.01 0.10 −0.06 −0.01 0.10−0.07 Methocel E15LV 0.01 0.00 −0.06 0.00 0.00 −0.06 Methocel A15LV−0.02 −0.01 −0.07 −0.02 −0.01 −0.07 PS80 −0.01 0.00 −0.04 −0.01 −0.01−0.04 PPG2000 0.01 0.02 −0.04 0.01 0.01 −0.04

TABLE 5 Stabilizing DLS effective diameter (nm) excipient 0 hrs 16 hrs40 hrs Methocel K3LV 12.2 12.1 12.1 Methocel E3LV 11.6 12.0 12.3Methocel E15LV 11.8 12.3 11.9 Methocel A15LV 12.2 12.7 11.9 PS80 11.712.3 12.3 PPG2000 11.9 12.5 11.6

Light absorbance and DLS measurements of samples after exposure tovigorous shear indicate that low molecular weight HPMC and MC was ableto protect cetuximab from degrading to the same extent as PS80 andPPG2000.

Example 4: FlowCAM Analysis of Stressed Cetuximab Formulations

Samples containing about 2 mg/mL cetuximab in phosphate buffer at pH 7with 200 ppm excipient prepared in accordance with Example 3 wereanalyzed for insoluble particles by dynamic flow imaging using a FlowCamVS1 (Fluid Imaging Technologies, Scarborough, Me.). The FlowCam wasequipped with a 20× objective lens and a 50 micron depth flow cell, andoperated at a flow rate of 0.03 mL/min. Measurements were made induplicate using a sample volume of 1.0 mL per run. Particles werecounted and grouped into four categories by equivalent sphericaldiameter using the VisualSpreadsheet particle analysis software providedwith the FlowCam instrument, with the reported value for each particleclass being an average from the two sample runs. The results are setforth in Table 6 below.

TABLE 6 Average number of particles per mL after 40 hours shaking: 2-10μm 10-20 μm 20-50 μm >50 μm particles particles particles particlesStabilizing St. St. St. St. excipient Avg. Dev. Avg. Dev. Avg. Dev. Avg.Dev. Methocel 2564 640 309 46 113 3 0 0 K3LV Methocel 893 39 46 15 9 3 00 E3LV Methocel 1773 328 481 7 86 18 0 0 E15LV Methocel 2021 93 145 2831 6 0 0 A15LV PS80 383 32 31 13 6 6 0 0 PPG2000 493 56 15 9 0 0 0 0

Example 5: Testing of PPG and PEG as Stabilizing Excipients

This example compares the effect of the following additives asstabilizing excipients: propylene glycol (PG), dipropylene glycol (DPG),tripropylene glycol (TPG), polypropylene glycol, M_(n) ˜425 g/mol(PPG425), polypropylene glycol, M_(n) ˜725 g/mol (PPG725), polyethyleneglycol, M_(n) ˜400 g/mol (PEG400), and Polysorbate 80 (PS80).

An ERBITUX® formulation was prepared as follows. A commercial cetuximab(ERBITUX®) drug product distributed in the U.S. by Eli Lilly & Co. wasacquired. According to the FDA drug label, the commercial formulationcontained 2 mg/mL cetuximab, 8.48 mg/mL sodium chloride, 1.88 mg/mLsodium phosphate dibasic heptahydrate and 0.41 mg/mL sodium phosphatemonobasic monohydrate.

The ERBITUX® sample was then reformulated in 15 mM sodium phosphate and4.8 mg/mL sodium chloride at pH 7 in the presence of about 200 ppmstabilizing excipient in the following way. Buffer solutions wereprepared by dissolving approximately 0.1 g sodium phosphate monobasicdihydrate (Sigma-Aldrich, St. Louis, Mo.), 0.24 g sodium chloride(Sigma-Aldrich, St. Louis, Mo.) and about 0.01 g of the desiredstabilizing excipient in deionized water, and diluted to a final mass ofabout 50 g with additional deionized water. The solution pH of eachbuffer was adjusted to about 7 with the dropwise addition of either 5 Msodium hydroxide or 1 M sodium hydroxide. Buffers were filtered through0.2 micron sterile polyethersulfone syringe filter (GE HealthcareBiosciences, Pittsburgh, Pa.), and 3.8 mL of each buffer added tosterile 5 mL polypropylene tubes. Amicon Ultra 15 centrifugalconcentrator tubes with a 30 kDa nominal molecular weight cut-off(EMD-Millipore, Billerica, Mass.) were rinsed with deionized water,filled with 14 mL of Erbitux sample, and centrifuged in a Sorvall LegendRT centrifuge for about 25 minutes at about 3200×g and 25° C. to a finalretentate volume of about 1 mL or a concentration of about 30 mg/mLcetuximab. The filtrate was then removed and about 0.27 mL was added toeach buffer containing 5 mL sterile polypropylene tube, filtered through0.2 micron sterile syringe filters.

The resulting cetuximab formulations in the 5 mL polypropylene tubes,having a concentration of about 2 mg/mL cetuximab and final volume ofabout 4 mL, were placed on a Daigger Scientific (Vernon Hills, Ill.)Labgenius orbital shaker at 275 rpm. After 16 hours and 39 hours ofcontinuous shaking at ambient temperature, samples were analyzed bylight absorbance in a Thermo Fisher Scientific Evolutionspectrophotometer with a 10 mm path length cuvette, and by dynamic lightscattering (DLS) with a ZetaPlus from Brookhaven Instruments(Holtsville, N.Y.).

Absorbance at 350 nm and 550 nm was utilized as a measurement ofturbidity, with higher absorbance indicating more degradation of theproduct due to the formation of more insoluble particulates. Absorbancevalues are reported in Absorbance Units (AU) from the spectrophotometermeasurements. These results are presented in Table 7.

Light scattering measurements yielded an effective diameter innanometers and Instead, the DLS measurements were used as a moresensitive way to monitor aggregation of the protein than turbidity. TheDLS results are summarized in Table 8.

TABLE 7 Absorbance Absorbance Test Stabilizing at 350 nm (AU) at 550 nm(AU) No. Excipient 0 hrs 16 hrs 39 hrs 0 hrs 16 hrs 39 hrs 5.1 PPG425−0.006 −0.007 −0.019 −0.002 −0.005 −0.017 5.2 PS80 −0.025 −0.005 −0.013−0.019 −0.002 −0.016 5.3 PEG400 −0.026   0.072   0.395 −0.019   0.044  0.192 5.4 PG −0.018   0.156   0.53  −0.013   0.089   0.303 5.5 DPG−0.023   0.355   0.671 −0.019   0.192   0.366 5.6 TPG   0.052   0.184  0.594   0.055   0.104   0.328 5.7 PPG725 −0.015 −0.008 −0.034 −0.012  0.005 −0.033

TABLE 8 Stabilizing DLS Effective Diameter (nm) Test No. Excipient 0 hrs16 hrs 39 hrs 5.1 PPG425 11.6 11.8 11.5 5.2 PS80 11.9 11.5 11.7 5.3PEG400 11.7 4430 2313 5.4 PG 11.4 3942 1697 5.5 DPG 11.6 6182 2077 5.6TPG 11.4 4691 2463 5.7 PPG725 11.5 11.6 11.7

Results from light absorbance and DLS particle size demonstrate thatpolypropylene glycol was more effective in preventing aggregation ofcetuximab after severe agitation and high exposure to air/liquidinterface than polyethylene glycol of a similar molecular weight.Polypropylene glycol also demonstrated better performance than propyleneglycol or its dimer or trimer. Polypropylene glycol and polysorbate 80had similar absorbance and DLS results.

Example 6: Testing of Stabilizing Excipients

This example compares the effect of the following additives asstabilizing excipients: hydroxypropyl methylcellulose, M_(n) ˜10,000(HPMC), PPG425, acesulfame K, saccharin, leucine, and sodium propionate(Na Propionate).

An ERBITUX® formulation was prepared as follows. A commercial cetuximab(ERBITUX®) drug product distributed in the U.S. by Eli Lilly & Co. wasacquired. According to the FDA drug label, the commercial formulationcontained 2 mg/mL cetuximab, 8.48 mg/mL sodium chloride, 1.88 mg/mLsodium phosphate dibasic heptahydrate and 0.41 mg/mL sodium phosphatemonobasic monohydrate.

The ERBITUX® sample was then reformulated in 15 mM sodium phosphate atpH 7 in the presence of various stabilizing excipients in the followingway. Buffer solutions containing excipients were prepared by dissolvingapproximately 0.1 g sodium phosphate monobasic dihydrate (Sigma-Aldrich,St. Louis, Mo.) and the desired excipients in deionized water andadjusting the pH of the solution to 7 with the dropwise addition ofeither 1 M sodium hydroxide or 1 M hydrochloric acid. Solutions werediluted to a final volume of 50 mL in a volumetric flask with additionaldeionized water. Buffers were filtered through 0.2 micron sterilepolyethersulfone syringe filter (GE Healthcare Biosciences, Pittsburgh,Pa.), and 3.8 mL of each buffer added to sterile 5 mL polypropylenetubes. Amicon Ultra 15 centrifugal concentrator tubes with a 30 kDanominal molecular weight cut-off (EMD-Millipore, Billerica, Mass.) wererinsed with deionized water, filled with 14 mL of Erbitux sample, andcentrifuged in a Sorvall Legend RT centrifuge for about 25 minutes atabout 3200×g and 25° C. to a final retentate volume of about 1 mL or aconcentration of about 30 mg/mL cetuximab. The filtrate was then removedand about 0.28 mL was added to each buffer containing 5 mL sterilepolypropylene tube, filtered through 0.2 micron sterile syringe filters.

The resulting cetuximab formulations in the 5 mL polypropylene tubes,having a concentration of about 2 mg/mL and final volume of about 4 mL,were placed on a Daigger Scientific (Vernon Hills, Ill.) Labgeniusorbital shaker at 275 rpm. After 16 hours and 36 hours of continuousshaking at ambient temperature, samples were analyzed by opticalabsorbance in a Thermo Fisher Scientific Evolution spectrophotometerwith a 10 mm path length cuvette and by dynamic light scattering (DLS)with a ZetaPlus from Brookhaven Instruments (Holtsville, N.Y.).

Absorbance at 350 nm and 550 nm was utilized as a measurement ofturbidity, with higher absorbance indicating more degradation of theproduct after stress, due to the formation of more insolubleparticulates. Absorbance values are reported in Absorbance Units (AU)from the spectrophotometer measurements. In some cases, samples wereallowed to shake for a total of 128 hours and absorbance measurementsobtained. The results are presented in Table 9 below.

Dynamic light scattering (DLS) measurements yielded an effectivediameter in nanometers and were not corrected for slight differences inviscosity and refractive index of the buffers. Instead, the DLSmeasurements were used as a more sensitive way than turbidity formonitoring protein aggregation. The results are summarized in Table 10below.

TABLE 9 Excipient 1 Excipient 2 Conc. Conc. Test (g/50 (g/50 ABS 350 nm(AU) ABS 550 nm (AU) No. Name mL) Name mL) 0 hrs 16 hrs 36 hrs 0 hrs 16hrs 36 hrs 6.1 HPMC 0.2 NaCl 0.23 0.00 0.01 0 −0.01 0.00 0.00 6.2 KS0.75 NaCl 0.23 0.00 0.11 0.15 −0.02 0.06 0.07 6.3 LBA 0.75 NaCl 0.230.02 0.04 1.15 −0.03 0.02 0.72 6.4 PPG425 0.42 NaCl 0.23 0.02 0.04 0.01−0.03 0.04 0.02 6.5 Acesulfame 0.75 NaCl 0.23 0.02 0.13 1.01 0.02 0.070.59 K 6.6 Saccharin 0.75 NaCl 0.23 0.00 1.53 2.59 −0.03 0.87 1.88 6.7Leucine 0.49 NaCl 0.23 0.03 0.22 0.44 −0.03 0.12 0.28 6.8 Na 0.75 — —−0.01 0.37 1.51 −0.02 0.21 0.89 Propionate 6.9 None — — — −0.02 0.631.17 −0.02 0.37 0.67 (Erbitux commercial sample)

TABLE 10 DLS Effective Diameter (nm) Test No. Excipients 0 hrs 16 hrs 36hrs 128 hrs 6.1 See Table 9 14.2 14.2 15.3 N/A 6.2 See Table 9 11.9 41184626 4098 6.3 See Table 9 15.3 1588 7277 N/A 6.4 See Table 9 11.9 12.312.1 12.3 6.5 See Table 9 11.5 4176 6121 N/A 6.6 See Table 9 11.9 91923303 N/A 6.7 See Table 9 11.9 7363 4674 4326 6.8 See Table 9 12.6 39363902 N/A 6.9 See Table 9 11.5 6055 8840 N/A

An Agilent 1100 series HPLC with auto-sampler was employed to conductsize-exclusion chromatography (SEC) analysis of the above formulationsto monitor loss of cetuximab monomer after exposure to shaking stress.Samples were run on a TSKgel Super SW3000 4.6 mm×30 cm column (TosohBioscience) with an injection volume of 15 microliters and a flow rateof 0.35 mL/min. An Agilent 1100 series diode array detector was used tomeasure eluate absorbance at 280 nm with a bandwidth of 4 nm. The columntemperature was set to 25° C., and the mobile phase was 0.2 M sodiumphosphate, pH 6.8. Change in area of the monomer peak before and afterstress was used to quantify monomer loss. Monomer peak area aftershaking stress was reported as a percentage of the monomer peak areabefore stress exposure. These results are presented in Table 11 below.

TABLE 11 % monomer retained after shaking Test No. Excipients 16 hrs 36hrs 6.1 See Table 9 100% 101% 6.2 See Table 9  98%  99% 6.3 See Table 9 97%  73% 6.4 See Table 9  99% 100% 6.5 See Table 9  97%  86% 6.6 SeeTable 9  70%  22% 6.7 See Table 9 N/A N/A 6.8 See Table 9  93%  73% 6.9See Table 9  89%  81%

Results from light absorbance, DLS particle size and size-exclusion HPLC(SE-HPLC) demonstrate that hydroxypropyl methyl cellulose andpolypropylene glycol prevent the aggregation of cetuximab after severeagitation and high exposure to air/liquid interface. In the presence ofeither excipient, formation of visible particles was prevented, as shownby absorbance data. Preservation of initial monomer size, shown by DLSparticle sizing data, indicates suppression of soluble aggregateformation. SE-HPLC corroborates these measurements, demonstratingessentially no loss of monomer in sample.

The formulation with potassium sorbate also showed significantimprovement over the commercial ERBITUX® product in suppressingturbidity after shaking.

Example 7: Shaker Stress of Erbitux Formulations with Different Amountsof PPG425

An ERBITUX® formulation was prepared as follows. A commercial cetuximab(ERBITUX®) drug product distributed in the U.S. by Eli Lilly & Co. wasacquired. According to the FDA drug label, the commercial formulationcontained 2 mg/mL cetuximab, 8.48 mg/mL sodium chloride, 1.88 mg/mLsodium phosphate dibasic heptahydrate and 0.41 mg/mL sodium phosphatemonobasic monohydrate.

The ERBITUX® sample was then reformulated in 15 mM sodium phosphate and4.8 mg/mL sodium chloride at pH 7 in the presence of varying amounts ofpolypropylene glycol having an average molecular weight of about 425g/mol (PPG425) in the following way. Buffer solutions containing PPG425were prepared by dissolving approximately 0.1 g sodium phosphatemonobasic dihydrate (Sigma-Aldrich, St. Louis, Mo.) and the desiredexcipients in deionized water and adjusting the pH of the solution to 7with the dropwise addition of 1 M sodium hydroxide. Solutions werediluted to a final volume of 50 mL in a volumetric flask with additionaldeionized water. In some cases, a buffer containing no PPG425 was addedto a buffer containing PPG425 in such a way as to obtain a buffer with alower PPG425 concentration with the same phosphate and sodium chlorideconcentrations at pH about 7. Buffers were filtered through 0.2 micronsterile polyethersulfone syringe filter (GE Healthcare Biosciences,Pittsburgh, Pa.), and 3.8 mL of each buffer added to sterile 5 mLpolypropylene tubes. Amicon Ultra 15 centrifugal concentrator tubes witha 30 kDa nominal molecular weight cut-off (EMD-Millipore, Billerica,Mass.) were rinsed with deionized water, filled with 14 mL of Erbituxsample, and centrifuged in a Sorvall Legend RT centrifuge for about 25minutes at about 3200×g and 25° C. to a final retentate volume of about1 mL or a concentration of about 30 mg/mL cetuximab. The filtrate wasthen removed and about 0.28 mL was added to each buffer containing 5 mLsterile polypropylene tube, filtered through 0.2 micron sterile syringefilters.

The resulting cetuximab formulations in the 5 mL polypropylene tubes,having a concentration of about 2 mg/mL cetuximab and final volume ofabout 4 mL, were placed on a Daigger Scientific (Vernon Hills, Ill.)Labgenius orbital shaker at 275 rpm. After 23 hours and 54 hours ofcontinuous shaking at ambient temperature, samples were analyzed bylight absorbance in a Thermo Fisher Scientific Evolutionspectrophotometer with a 10 mm path length cuvette and by dynamic lightscattering (DLS) with a ZetaPlus from Brookhaven Instruments Corp.(Holtsville, N.Y.).

Absorbance at 350 nm and 550 nm was utilized as a measurement ofturbidity, with higher absorbance indicating more degradation of theproduct after stress in the form of more insoluble particulates.Absorbance values are reported in Absorbance Units (AU) from thespectrophotometer measurements. These results are presented in Table 12below.

Dynamic light scattering (DLS) measurements yielded an effectivediameter in nanometers and were not corrected for slight differences inviscosity and refractive index of the buffers. Instead, the DLSmeasurements were used as a more sensitive way than turbidity formonitoring protein aggregation. These results are summarized in Table 13below.

TABLE 12 PPG425 Test Conc ABS 350 nm (AU) ABS 550 nm (AU) No. (mg/mL) 0hrs 23 hrs 54 hrs 0 hrs 23 hrs 54 hrs 7.1 0.5 −0.03 −0.04 −0.02 −0.02−0.03 −0.01 7.2 1 −0.02 −0.04 0.00 −0.01 −0.03 0.00 7.3 2 −0.03 −0.040.01 −0.03 −0.02 0.01 7.4 5 −0.03 −0.04 0.04 −0.02 −0.02 0.05

TABLE 13 PPG425 Conc DLS Effective Diameter (nm) Test No. (mg/mL) 0 hrs23 hrs 54 hrs 7.1 0.5 11.3 11.7 11.3 7.2 1 11.6 11.4 11.5 7.3 2 11.611.6 11.5 7.4 5 11.6 11.9 11.7

An Agilent 1100 series HPLC with auto-sampler was employed to conductsize-exclusion chromatography (SEC) analysis of the above formulationsto monitor loss of cetuximab monomer after exposure to shaking stress.Samples were run on a TSKgel Super SW3000 4.6 mm×30 cm column (TosohBioscience) with an injection volume of 15 microliters and a flow rateof 0.35 mL/min. An Agilent 1100 series diode array detector was used tomeasure eluate absorbance at 280 nm with a bandwidth of 4 nm. The columntemperature was set to 25° C., and the mobile phase was 0.2 M sodiumphosphate, pH 6.8. Change in area of the monomer peak before and afterstress was used to quantify monomer loss. Monomer peak area aftershaking stress was reported as a percentage of the monomer peak areabefore stress exposure. These results are set forth in Table 14 below.

TABLE 14 PPG425 % monomer retained after Conc. shaking stressFormulation (mg/mL) 23 hrs 54 hrs 7.1 0.5  98%  98% 7.2 1  99%  99% 7.32 100%  99% 7.4 5  99%  98%

Results from light absorbance, DLS particle size and size-exclusion HPLC(SE-HPLC) demonstrate the impact polypropylene glycol from 0.5 mg/mL to5 mg/mL had in preventing aggregation of cetuximab after severeagitation and high exposure to air/liquid interface. Even in thepresence of even low excipient concentration, formation of visibleparticles was prevented, as shown by absorbance data. Preservation ofinitial monomer size shown by DLS particle sizing data indicatessuppression of soluble aggregate formation. SE-HPLC corroborates thesemeasurements demonstrating essentially no loss of monomer in sample.

Example 8: Agitation Stress of Formulations Containing 10 mg/mLCetuximab

This example compares the effect of the following additives in reducingparticle formation in an agitated cetuximab formulation.

Materials:

Carboxymethylhydroxypropyl guar, CMHPG (Sigma-Aldrich, St. Louis)

Maltrin M100 (Grain Processing Corporation, Muscatine, Iowa)

Polyvinylpyrrolidone, 10 kDa (Sigma-Aldrich, St. Louis, Mo.)

Poly(2-ethyl-2-oxazoline), 5 kDa (Sigma-Aldrich, St. Louis, Mo.)

Poly(2-ethyl-2-oxazoline), 50 kDa (Sigma-Aldrich, St. Louis, Mo.)

Polypropylene glycol 1000 (Sigma-Aldrich, St. Louis, Mo.)

Pluronic F68 (BASF, Florham Park, N.J.)

Polysorbate 80 (Sigma-Aldrich, St. Louis, Mo.)

A commercial cetuximab (ERBITUX®) drug product distributed in the U.S.by Eli Lilly & Co. was acquired. According to the FDA drug label, thecommercial formulation contained 2 mg/mL cetuximab, 8.48 mg/mL sodiumchloride, 1.88 mg/mL sodium phosphate dibasic heptahydrate and 0.41mg/mL sodium phosphate monobasic monohydrate. The Erbitux sample wasreformulated in 10 mM sodium phosphate and 140 mM sodium chloride at pH7 in the presence of about 100 ppm or about 200 ppm of stabilizingexcipient in the following way. A stock buffer solution was prepared bydissolving 1.4 g sodium phosphate monobasic monohydrate (Sigma-Aldrich,St. Louis, Mo.), and about 8.2 g sodium chloride (Sigma-Aldrich, St.Louis, Mo.) in deionized water, and diluted to a final volume of 1 Lwith additional deionized water. The solution pH was adjusted to about 7with the dropwise addition of 10 M sodium hydroxide. Stabilizingexcipient was dissolved in the resulting buffer by adding 0.02 g or 0.04g excipient to 50 mL of the stock buffer at pH 7. Excipient solutionswere filtered through a 0.2 micron sterile polyethersulfone syringefilter (GE Healthcare Biosciences, Pittsburgh, Pa.), and 0.25 mL of eachexcipient solution added to a sterile 2 mL polypropylene tube along withstock buffer containing no excipient to achieve a volume of 0.71 mLprior to addition of concentrated cetuximab solution.

Amicon Ultra 15 centrifugal concentrator tubes with a 30 kDa nominalmolecular weight cut-off (EMD-Millipore, Billerica, Mass.) were rinsedwith deionized water, filled with 10 mL of Erbitux sample, andcentrifuged in a Sorvall Legend RT centrifuge at about 3200×g and 23° C.to a final retentate volume of about 0.5 mL. The filtrate was thenremoved and about 0.29 mL was added to each sterile polypropylene tube,filtered through 0.2 micron sterile syringe filters.

The resulting cetuximab formulations in the 2 mL polypropylene tubes,having a concentration of about 10 mg/mL cetuximab and a final volume ofabout 1 mL, were placed on a Daigger Scientific (Vernon Hills, Ill.)Labgenius orbital shaker at 275 rpm. Samples were analyzed after 40hours of continuous shaking by dynamic flow imaging with a FlowCam VS1(Fluid Imaging Technologies, Scarborough, Me.).

The FlowCam was equipped with a 20× objective lens and a 50 micron depthflow cell, and operated at a flow rate of 0.03 mL/min. Measurements weremade using a sample volume of 0.5 mL per run. Particles were counted andreported in four categories according to equivalent spherical diameterusing the VisualSpreadsheet particle analysis software included with theinstrument.

TABLE 15 Excipient conc. FlowCam analysis (particles per mL) ExcipientID (ppm) 2-10 μm 10-20 μm 20-50 μm >50 μm Total Polyvinylpyrrolidone,100 564,764 126,021 5560 99 696,444 10K Polysorbate 80 100 3160 172 49 03381 Pluronic F68 100 357 12 0 0 369 Poly(2-ethyl-2- 100 2230 320 0 02550 oxazoline), 5K Poly(2-ethyl-2- 200 46,040 14,826 6090 431 67,387oxazoline), 50K PPG1000 100 1771 12 12 0 1795 CMHPG 100 1,418,745659,587 308,738 14,509 2,401,579 Maltrin M100 200 1,024,815 705,887503,525 102,770 2,336,997 None 0 2,962,530 756,922 131,824 6697 3857973

Example 9: Polyvinyl Alcohol as Stabilizer Against Agitation Stress inCetuximab Formulations

This example compares the effect of the following additives in reducingparticle formation in an agitated cetuximab formulation.

Materials:

Polyvinyl alcohol, 80% hydrolyzed, 9-10 kDa (Sigma-Aldrich, St. Louis,Mo.)

Polyvinyl alcohol, 87-89% hydrolyzed, 146-186 kDa (Sigma-Aldrich, St.Louis, Mo.)

Polypropylene glycol 1000 (Sigma Aldrich, St. Louis, Mo.)

A commercial cetuximab (ERBITUX®) drug product distributed in the U.S.by Eli Lilly & Co. was acquired. According to the FDA drug label, thecommercial formulation contained 2 mg/mL cetuximab, 8.48 mg/mL sodiumchloride, 1.88 mg/mL sodium phosphate dibasic heptahydrate and 0.41mg/mL sodium phosphate monobasic monohydrate. The Erbitux sample wasreformulated in 10 mM sodium phosphate and about 140 mM sodium chlorideat pH 7 in the presence of about 50 ppm or about 100 ppm of stabilizingexcipient in the following way. Buffer solutions were prepared bydissolving 0.355 g sodium phosphate monobasic monohydrate(Sigma-Aldrich, St. Louis, Mo.), and about 2 g sodium chloride(Sigma-Aldrich, St. Louis, Mo.) in deionized water, and diluted to afinal volume of 250 mL with additional deionized water. The solution pHwas adjusted to about 7 with the dropwise addition of either 10 M sodiumhydroxide. Stabilizing excipient was dissolved in the resulting bufferby adding 0.02 g excipient to 50 mL of the phosphate buffered saline atpH 7. Excipient solutions were filtered through 0.2 micron sterilepolyethersulfone syringe filter (GE Healthcare Biosciences, Pittsburgh,Pa.), and either 1.0 mL or 0.5 mL of each excipient solution added tosterile 5 mL polypropylene tubes along with buffer containing noexcipient to achieve a volume of about 3.8 mL prior to addition ofconcentrated cetuximab solution.

Amicon Ultra 15 centrifugal concentrator tubes with a 30 kDa nominalmolecular weight cut-off (EMD-Millipore, Billerica, Mass.) were rinsedwith deionized water, filled with 8.5 mL of Erbitux sample, andcentrifuged in a Sorvall Legend RT centrifuge at about 3200×g and 23° C.to a final retentate volume of about 0.5 mL. The filtrate was thenremoved and about 0.21 mL was added to each sterile polypropylene tube,filtered through 0.2 micron sterile syringe filters.

The resulting cetuximab formulations in the 5 mL polypropylene tubes,having a concentration of about 2 mg/mL cetuximab and final volume ofabout 4 mL, were placed on a Daigger Scientific (Vernon Hills, Ill.)Labgenius orbital shaker at 275 rpm. After about 40 hours of continuousshaking, samples were pulled and analyzed by dynamic light scatteringwith a ZetaPlus from Brookhaven Instruments Corp. (Holtsville, N.Y.),and by dynamic flow imaging with a FlowCam VS1 (Fluid ImagingTechnologies, Scarborough, Me.).

TABLE 16 DLS effective Excipient particle size (nm) Conc. Final (afterIdentity (ppm) Initial 40 hrs shaking) Polyvinyl alcohol, 100 11.4 11.480% hydrolyzed Polyvinyl alcohol, 50 11.9 25,202 80% hydrolyzedPolyvinyl alcohol, 100 11.9 12.0 87-89% hydrolyzed Polyvinyl alcohol, 5013.2 14.4 87-89% hydrolyzed PPG1000 100 11.8 12.4 None 0 11.6 6817

The FlowCam was equipped with a 20× objective lens and a 50 micron depthflow cell, and operated at a flow rate of 0.03 mL/min. Measurements weremade using a sample volume of 0.5 mL per run. Particles were counted andreported in four categories according to equivalent spherical diameterusing the VisualSpreadsheet particle analysis software included with theinstrument.

TABLE 17 Excipient FlowCam analysis after 40 hrs shaking (particles/mL)Identity Conc. (ppm) 2-10 μm 10-20 μm 20-50 μm >50 μm Polyvinyl alcohol,100 1988 171 55 177 80% hydrolyzed Polyvinyl alcohol, 50 153,069 22,15310,960 1980 80% hydrolyzed Polyvinyl alcohol, 100 335 61 6.1 0 87-89%hydrolyzed Polyvinyl alcohol, 50 128,607 10,475 4130 775 87-89%hydrolyzed PPG1000 100 506 30 55 0 None 0 2,936,829 563,874 144,868 6800

In all cases the presence of the additive significantly reduced thenumber of particles generated during the agitation stress compared tosample with no additive, as demonstrated by the FlowCam data.

Example 10: The Impact of the Cellulosic Modification on the Stabilityof Cetuximab Formulations

Two modified cellulosic materials, hydroxypropyl cellulose (HPC), andsodium carboxymethyl cellulose (CMC), were examined for their ability tostabilize cetuximab solutions to particle formation. The excipients werepurchased from Sigma-Aldrich (St. Louis, Mo.) and used without furthermodification. Cetuximab was purchased under the trade name Erbitux® (EliLilly, Indianapolis, Ind.) from Clinigen Group (Yardley, Pa.). The HPChad a weight-average molecular weight of 80,000 and a number-averagemolecular weight of 10,000. The CMC had a weight-average molecularweight of 90,000. The number-average was not reported for the CMC. Thecetuximab concentration was 2 mg/mL in all experiments. The HPC and CMCconcentrations are listed in Table 18. A control sample with nostabilizing excipient was also prepared. All solutions were prepared inphosphate buffered saline, pH 7. Four mL of each sample was placed intosterile 5 mL polypropylene tubes. The samples were stressed by shakingon an orbital shaker at 275 rpm for 40 hours. Particulate formation wasquantified by measuring the absorbance at 350 nm and the particle sizewas measured using dynamic light scattering (DLS). A Brookhaven ZetaPlusinstrument was used to perform the DLS experiments. The cumulantsexpansion was fit the DLS intensity autocorrelation functions toestimate the particle sizes. DLS measurements were made both prior toand after shaking.

Solutions containing HPC are less turbid than the control (Table 18) andthe apparent particle size does not change during the experiment,indicating that HPC is effective in stabilizing cetuximab towardsparticle formation. However, solutions containing CMC have turbiditiesand final particle sizes similar to that of the control, indicating thatCMC is not effective in stabilizing cetuximab towards particleformation. The results here illustrate that the type of modification isimportant in the ability of the cellulosic material to protect againstparticulate formation in protein solutions.

TABLE 18 Cellulosic Absorbance Initial DLS Final DLS concentration at350 nm particle size particle size Sample (ppm) (AU) (nm) (nm) ControlN/A 0.749 12.2 10,421 CMC 2151 0.560 14.1 13,936 CMC 203 0.628 11.917,620 HPC 1850 0.071 14.0 13.3 HPC 199 0.065 11.9 11.8

Example 11: Excipients that Stabilize Cetuximab Formulations to ParticleFormation

In this example, cetuximab at 2 mg/mL is stressed in the presence ofseveral different stabilizing excipients. The excipients are polyvinylpyrrolidone (PVP) with weight-average molecular weight of 40,000,polyvinyl alcohol (PVOH) with weight-average molecular weight of13,000-23,000 and 87-89% hydrolyzed residues, 2-hydroxyethyl cellulose(HEC) with viscosity-average molecular weight of 90,000, andpoly(2-ethyl-2-oxazoline) (PDX5000) with number-average molecular weightof 5000 and polydispersity less than or equal to 1.2, and aspartame. Theexcipients were purchased from Sigma-Aldrich (St. Louis, Mo.) and usedwithout further modification. Cetuximab was purchased under the tradename ERBITUX® (Eli Lilly, Indianapolis, Ind.) from Clinigen Group(Yardley, Pa.). The concentrations of each excipient are listed in Table19. A control sample was also prepared with no stabilizing excipient.All experiments were performed in a phosphate buffered saline at pH 7.Four mL of each sample was put into sterile 5 mL polypropylene tubes,which were then placed on an orbital shaker set to 275 rpm. The sampleswere shaken for 40 hours, after which they were analyzed for particulateformation by an absorbance measurement at 405 nm to estimate turbidityand the total number of particles were counted using a FlowCam imagingdevice. The turbidity measurements were performed with a BioTek Synergyplate reader and corrected for the path length of the liquid height inthe microplate. The FlowCam was equipped with a 20× objective lens and a50 μm depth flow cell, and operated at a flow rate of 0.03 mL/min.Measurements were made using a sample volume of 0.5 mL per run. Thecontrol sample was run through the FlowCam last and partially cloggedthe flow cell, which prevented an accurate particle count. This makesthe number listed in Table 19 a lower bound on the total number ofparticles. At the use levels indicated in Table 19, all of the additivesstabilize cetuximab to particulate formation as indicated by a reductionin the absorbance at 405 nm and a reduction in the total number ofparticles per mL.

TABLE 19 Excipient % Number % concen- Absorbance Reduction of Reductiontration at 405 nm of ABS405 particles in particles Sample (ppm) (AU) nmper mL per mL Control N/A 0.340 0 >1,184,884 0 PVP 1801 0.044 8714,868 >98.7 PVOH 197 0.032 90 898 >99.9 HEC 199 0.041 88 7559 >99.4POX5000 197 0.040 88 15,112 >98.7 Aspartame 5886 0.066 81 423,636 >64.2

Example 12: The Foaming Propensity of Stabilizing Excipients

Solutions of concentration 1000 ppm w/v of poly(propylene glycol) withM_(n) 1000 (PPG1000, Sigma Aldrich, St. Louis, Mo.),poly(2-ethyl-2-oxazoline) with M_(n) 5000 and PDI ≦1.2 (POX5000, SigmaAldrich, St. Louis, Mo.), Methocel E3LV (Dow Chemical Company, Midland,Mich.), polysorbate 80 (PS80, Sigma Aldrich, St. Louis, Mo.), andPluronic F68 (F68, BASF Corporation) were prepared using ultrapuredeionized water (18.2 MΩ·cm at 25° C.). 3 mL of each solution was placedinto a 5-mL polypropylene tube and vortexed on a Mini Vortex Mixer (VWR,Radnor, Pa.) on mixer setting #8 for 15 seconds. The foam heights weremeasured after vortexing and are listed in Table 20. The times for thefoams to dissipate were also recorded and are listed in Table 20. Thefoams for the POX5000 and F68 samples did not dissipate over the courseof the experiment. The stopping points are listed in Table 20.

TABLE 20 Excipient Foam height (in) Foam dissipation time (s) PPG10000.25 4 POX5000 0.63 27 Methocel E3LV 1.00 >1125 PS80 0.25 7 F68 1.25>1125

Example 13: The Recovery of Stabilizing Excipients after Ultrafiltration

Solutions of concentration 1000 ppm w/v of poly(propylene glycol) withM_(n) 1000 (PPG1000, Sigma Aldrich, St. Louis, Mo.),poly(2-ethyl-2-oxazoline) with M_(n) 5000 and PDI ≦1.2 (POX5000, SigmaAldrich, St. Louis, Mo.), Methocel E3LV (Dow Chemical Company, Midland,Mich.), polysorbate 80 (PS80, Sigma Aldrich, St. Louis, Mo.), andPluronic F68 (F68, BASF Corporation) were prepared using ultrapuredeionized water (18.2 MΩ·cm at 25° C.).

The filter devices used are Amicon Ultra-4 centrifugal devices with30,000 molecular weight cut-off (EMD Millipore). A Sorvall Legend RTCentrifuge was used to filter the feed volume through the membrane at4,000 rpm for 10 minutes at 25° C. An Agilent 1100 HPLC system withattached refractive index detector (RID) was used to measure theconcentration of the material in feed, retentate and filtrate volumes.

A standard curve was prepared initially for each solution.Concentrations of 1000, 700, 500, 400, 200 and 100 ppm were prepared andanalyzed on HPLC-RID to determine peak area. The peak area was thenplotted against concentration and a linear response was observed for allsolutions at a range from 100-1000 ppm.

The filter devices were pre-rinsed by addition of 4 mL of DI water andcentrifugation for 10 minutes at 4,000 rpm and 25° C. The filtered rinsewater was then discarded before the addition of 4 mL of 1000 ppmexcipient solution. The samples were then centrifuged using conditionsas stated above. The filtrate from filter devices was emptied into clean30 mL tubes (tare weighed) after centrifugation. The process wasrepeated four additional times for a total of 20 mL filtrate material.The total amount of filtrate was determined by mass. Each condition wasperformed in triplicate.

A volume of 100 μL of stock, retentate, and filtrate was removed and 20μL injections were prepared to determine peak area by refractive indexdetection (RID). Using the standard curve formula, the concentrationswere determined by inputting the peak areas. The amount of excipientrecovered in the filtrate and retentate was determined by multiplyingthe total filtrate and retentate volumes by the measured concentrations.The mass of excipient recovered in the filtrate was compared to theinitial mass added to filtration device to determine a percent recovery.

The percent recoveries of the excipients studied here are given in Table21. The recoveries of PPG1000, Methocel E3LV, POX5000, and Pluronic F68are greater than those of PS80.

TABLE 21 Mass Mass Mass excipient excipient Average excipient inrecovered Percent percentage added retentate in filtrate recoveredrecovered Excipient (mg) (mg) (mg) in filtrate in filtrate PS80 20.110.4 8.72 43.4% 40.5% 20.1 10.2 7.84 39.0% 20.1 10.0 7.87 39.1% PPG100020.2 0.35 20.7  102%  103% 20.2 0.35 20.6  102% 20.2 0.35 21.2  105%POX5000 20.2 0.45 19.9 98.4%  100% 20.2 0.45 20.4  101% 20.2 0.44 20.3 101% Methocel 16.7 4.71 13.8 82.6% 79.6% E3LV 16.7 4.12 12.9 77.4% 16.74.86 13.1 78.9% F68 23.8 0.81 21.55 90.6% 90.7% 23.8 0.81 21.62 90.8%23.8 0.84 21.58 90.7%

Example 14: Excipients that Stabilize Abatacept

Abatacept was purchased under the trade name ORENCIA® (Bristol-MeyersSquibb, Princeton, N.J.) from the Clinigen Group (Yardley, Pa.). Orenciawas reconstituted to 25 mg/mL abatacept in ultrapure deionized waterwith resistivity of 18.2 MΩ·cm (EMD Millipore, Billerica, Mass.) as perthe package insert instructions. A 14-mM monosodium phosphate buffer(Sigma Aldrich, St. Louis, Mo.), pH 7.5 with 25 mM NaCl (Sigma Aldrich,St. Louis, Mo.) was prepared. Stock solutions of concentration 2000 ppmby weight of poly(propylene glycol) with M_(n) 1000 (PPG1000, SigmaAldrich, St. Louis, Mo.), poly(2-ethyl-2-oxazoline) with M_(n) 5000 andPDI ≦1.2 (PDX5000, Sigma Aldrich, St. Louis, Mo.), and Methocel E3LV(Dow Chemical Company, Midland, Mich.) were prepared using thepreviously described buffer. Samples were prepared by mixing thereconstituted Orencia with the excipient stock solution and the bufferto a final protein concentration of 2.5 mg/mL, final excipientconcentrations of approximately 1800 ppm and 200 ppm. 1 mL of eachsample was placed into a sterile 2 mL polypropylene tube. The tubes wereshaken for 18 hours at 25° C. on a Multi-Therm Shaker (SouthwestScience, Roebling, N.J.). An unstressed control sample with no excipientwas also included (Sample 1, Table 22). The samples were assayed forapparent particle size by dynamic light scattering (DLS) and totalparticle count by FlowCam imaging. Forty μL of each sample was loadedinto a 384-well microplate (Aurora Microplates, Whitefish, Mont.). Airbubbles were removed from the microplate by centrifuging the plate at400×g for 1 minute. The plate was then assayed for apparent particlesize by DLS (DynaPro Plate Reader II, Wyatt, Santa Barbara, Calif.). Theinstrument control and data fitting were performed using the DYNAMICSsoftware package (Wyatt, Santa Barbara, Calif.). The incident wavelengthwas 830 nm and the scattering angle was 158°. The intensityautocorrelation functions were generated using five 5-second exposuresand were fit to the cumulants expansion to estimate the particlediffusivity. The apparent hydrodynamic radii (Rh) were calculated fromthe diffusivities via the Stokes-Einstein relation. Sub-visible particle(greater than 2 microns in size) formation was quantified using aFlowCam VS1 analyzer (Fluid Imaging Technologies, Scarborough, Me.). TheFlowCam was equipped with a 20× objective lens and a 50-micron depthflow cell, and operated at a flow rate of 0.03 mL/min. 0.5 mL of eachsample was assayed for particle counts.

All of the excipients in this example stabilize abatacept formulationsto a shaking stress as indicated by a decrease in the particle count andhydrodynamic size as compared to the control (Sample 2, Table 22).

TABLE 22 Excipient concentration Stressed? R_(h) Particles/ SampleExcipient (ppm) (Yes/No) (nm) mL 1 None N/A No 5.3 571 2 None N/A Yes65.6 292,413 3 PPG1000 1800 Yes 5.0 3591 4 POX5000 1750 Yes 7.8 1021 5Methocel 2020 Yes 5.3 2595 E3LV 6 PPG1000 200 Yes 5.1 4550 7 POX5000 195Yes 6.2 69,474 8 Methocel 225 Yes 5.1 2813 E3LV

Example 15: PPG1000 Ultrafiltration without Concentration

Poly(propylene glycol) 1000 (PPG1000), purchased from Sigma-Aldrich, wasprepared at a concentration of 1000 ppm (0.1%) in ultrapure deionized(DI) water (18.2 MΩ·cm). Polysorbate 80 (PS80), purchased fromSigma-Aldrich, was prepared at a concentration of 1000 ppm (0.1%) inultrapure deionized (DI) water (18.2 MΩ·cm). The PPG1000 and PS80solutions were processed by ultrafiltration in the following way. AmiconUltra-4 centrifugal filter devices with a 30,000 molecular weightcut-off (EMD Millipore) were pre-rinsed with 5 mL of DI water. A SorvallLegend RT Centrifuge was used to spin down the DI water to wash filtermembrane at 4000 rpm for 10 minutes at 24° C. A total of 3 washes werecompleted for a total wash volume of 15 mL of DI water before sampleswere placed in the filter devices. After rinsing the filter devices, 5mL of PPG1000 or PS80 at 0.1% was added and the devices were centrifugedat 4000 rpm for 5 minutes at 24° C. A volume of 100 μL of retentate andfiltrate were removed from the filtration devices for analysis using arefractive index detector (RID) in line with an Agilent 1100 HPLCsystem.

The relative concentrations of PPG1000 and PS80 in the startingsolution, the retentate, and the filtrate were measured with theHPLC/RID system. The retentate and filtrate peak areas listed in Table23 for PPG1000 are nearly identical, indicating that PPG1000 does notconcentrate in the retentate during ultrafiltration. In the sameultrafiltration conditions, PS80 concentrates in the retentate by afactor of 90 compared to the initial stock concentration and is depletedin the filtrate by a factor of 20 less than the initial stockconcentration as shown by the peak areas recorded in Table 23.

TABLE 23 Stock Test Solution Retentate Filtrate No. Stock solution (peakarea) (peak area) (peak area) 1 0.1% PS80 40,794 3,617,387 2,109 2 0.1%PS80 40,794 3,623,979 2,330 3 0.1% PS80 40,794 2,940,782 [no detectablePS80] 4 0.1% PPG1000 162,226 166,405 165,743 5 0.1% PPG1000 162,226164,225 165,307 6 0.1% PPG1000 162,226 163,976 167,556

EQUIVALENTS

While specific embodiments of the subject invention have been disclosedherein, the above specification is illustrative and not restrictive.While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims. Many variations of the inventionwill become apparent to those of skilled art upon review of thisspecification. Unless otherwise indicated, all numbers expressingreaction conditions, quantities of ingredients, and so forth, as used inthis specification and the claims are to be understood as being modifiedin all instances by the term “about.” Accordingly, unless indicated tothe contrary, the numerical parameters set forth herein areapproximations that can vary depending upon the desired propertiessought to be obtained by the present invention.

What is claimed is:
 1. A therapeutic formulation comprising atherapeutically-effective amount of a therapeutic protein and astabilizing amount of a polypropylene glycol polymer, wherein thepolypropylene glycol polymer has a number-average molecular weightbetween about 300 and
 5000. 2. The therapeutic formulation of claim 1,wherein the therapeutic protein is an antibody.
 3. The therapeuticformulation of claim 2, where the formulation is suitable for injection.4. The therapeutic formulation of claim 3, wherein the formulationfurther comprises an aqueous medium.
 5. The therapeutic formulation ofclaim 2, wherein the formulation contains between about 1 μg/mL andabout 1 mg/mL of the antibody.
 6. The therapeutic formulation of claim2, wherein the formulation contains at least about 100 mg/mL of theantibody.
 7. The therapeutic formulation of claim 1, wherein theformulation contains at least about 1 to about 500 ppm of thepolypropylene glycol polymer.
 8. The therapeutic formulation of claim 1,wherein the formulation contains at least about 10 to about 100 ppm ofthe polypropylene glycol polymer.
 9. The therapeutic formulation ofclaim 1, wherein the polypropylene glycol polymer has a number-averagemolecular weight of about 425 Daltons.
 10. The therapeutic formulationof claim 1, wherein the polypropylene glycol polymer is a linear polymercomprising at least two hydroxyl groups.
 11. The therapeutic formulationof claim 1, wherein the formulation does not contain an additionalsurfactant.
 12. The formulation of claim 1, further comprising a buffer.13. The therapeutic formulation of claim 1, wherein the polypropyleneglycol polymer is added in an amount effective to reduce degradation ofthe formulation by at least 50%, as compared to a control formulationlacking the polypropylene glycol polymer.
 14. The therapeuticformulation of claim 13, wherein the polypropylene glycol polymer isadded in an amount effective to reduce degradation of the formulation byat least 70%, as compared to a control formulation lacking thepolypropylene glycol polymer.
 15. The therapeutic formulation of claim14, wherein the polypropylene glycol polymer is added in an amounteffective to reduce degradation of the formulation by at least 90%, ascompared to a control formulation lacking the polypropylene glycolpolymer.
 16. The therapeutic formulation of claim 1, wherein thepolypropylene glycol polymer is added in an amount effective to reduceaggregation or precipitation of the therapeutic protein during a coldstorage condition.
 17. The therapeutic formulation of claim 1, whereinthe polypropylene glycol polymer is added in an amount effective toreduce aggregation or precipitation of the therapeutic protein during anelevated storage condition.
 18. The therapeutic formulation of claim 1,wherein the therapeutic formulation is resistant to foaming.
 19. Thetherapeutic formulation of claim 1, wherein the therapeutic formulationis resistant to micelle formation.
 20. The therapeutic formulation ofclaim 1, wherein the therapeutic formulation has improved stability ascompared to the control formulation lacking the polypropylene glycolpolymer, when the therapeutic formulation is exposed to a stresscondition.
 21. The therapeutic formulation of claim 20, wherein thestress condition is selected from the group consisting of agitationstress, exposure to air/water interfaces, contact w/plastic, glass, ormetal surfaces, filtration, column chromatography separation, viralinactivation, exposure to pH conditions between pH 2 and pH 5, pHexposure to pH conditions between pH 8 and pH 12, exposure toproteolytic enzymes, exposure to lipase enzymes, and exposure tomicrobiological contamination.
 22. The therapeutic formulation of claim20, wherein the stress condition is selected from the group consistingof oxidation, hydrolysis, proteolysis, deamidation, disulfidescrambling, photodegradation, and microbial degradation.
 23. A method ofimproving stability in a therapeutic formulation comprising atherapeutically-effective amount of a therapeutic protein by adding astability-improving amount of a polypropylene glycol polymer to thetherapeutic formulation, wherein the polypropylene glycol polymer has anumber-average molecular weight between about 300 and
 5000. 24. Thetherapeutic formulation of claim 23, wherein the polypropylene glycolpolymer has a number-average molecular weight of about 425 Daltons. 25.The method of claim 23, wherein the polypropylene glycol polymer reducesdegradation of the therapeutic formulation by at least 50%, as comparedto a control formulation lacking the polypropylene glycol polymer. 26.The method of claim 25, wherein the polypropylene glycol polymer reducesdegradation of the therapeutic formulation by at least 70%, as comparedto a control formulation lacking the polypropylene glycol polymer. 27.The method of claim 26, wherein the polypropylene glycol polymer reducesdegradation of the therapeutic formulation by at least 90%, as comparedto a control formulation lacking the polypropylene glycol polymer.